


String Theory

by ThatOnePsycho



Category: One Piece, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Action/Adventure, BAMF Midoriya Izuku, Dreams, Friendship, Good Parent Midoriya Inko, Midoriya Izuku Has a Quirk, Midoriya Izuku is a Ray of Sunshine
Language: English
Status: Completed
Published: 2021-03-05
Updated: 2021-03-05
Packaged: 2021-03-18 16:56:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,498
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29861205
Author URL: https://archiveofourown.org/users/ThatOnePsycho/pseuds/ThatOnePsycho
Summary: Midoriya Izuku's Quirk, String Theory, turned him into a living, breathing string factory. His body could create and manipulate hundreds of strings on demand. Kurogane Tashigi's Quirk, Armament, let her enhance anything she was touching. Together, they would become the greatest hero team the world had ever seen.
Relationships: Other Relationship Tags to Be Added
Comments: 8
Kudos: 32





	String Theory

_ Kugane Tashigi watched the boy with ash blond hair shove another down, a sound like firecrackers echoing across the playground. Reaching down, she picked up a stick, black jumping from her hand and up it. She stood back up, walking towards the boy when something swished passed her ear. A bunch of somethings. _

_ Pouting, the five year old pulled out the stupid glasses she had to wear and put them on, blinking at the green string stretching passed her and around the boy's arm. More firecrackers exploded in his hand while he turned towards her. _

_ "Let go of me!" He yelled, yanking on the strings and dragging someone forwards. Causing them to crash into Tashigi and knocking them both over, "Izuku!" _

_ "I-I'm not gonna let you be mean to him, Kacchan!" The boy with green hair scrambled up, jerking "Kacchan" around with the strings attached to his left hand fingers as he did. Kacchan growled, grabbing the strings with his other hand and yanking the green haired boy towards him harder, crackling going off as he hit the other boy across the face. _

_ "Leave him alone!" Tashigi snapped, picking up her stick and running towards them. Kacchan growled again, before looking towards his friends and shoving his hands in his pockets. _

_ "C'mon," he said, "this isn't fun anymore." _

_ "T-thanks," the boy that Kacchan had been originally bullying scrambled up, before bowing and running away. Tashigi turned towards the green haired boy sitting on the ground and rubbing the burn on his face. _

_ "Are you ok?" _

_ "Yeah," he said, "It'll go away by tomorrow. Always does. I'm Midoriya Izuku, sorry for… for you getting dragged into it." _

_ "I was gonna join anyways," she said, "I'm Kurogane Tashigi." _

\--- X  **Izuku** X---

" **There are no countdowns in real life** !"

Izuku launched a pair of green ropes from his sleeves at that, latching onto the end of the doorway into the fake city and throwing himself over the crowd. The ropes retraced and vanished as the wind forced him to squint, and he returned his left hand to its pocket. Dang, he wished he had his goggles.

Small strings, so thin they looked like nothing more than beams of green light when visible and as hard as he could make them, projected from his fingertips as he came flying towards the first bot, a three pointer. Viridian lashed through olive green before Izuku landed and kicked off. Behind him, the robot slid to ragged pieces. Watching another, a two pointer, round the corner Izuku pulled his hand back and-

Before the strings could fire forward, Izuku's hair stood on end and he swept down, a boy with blond hair looking at him with seething anger in his blue eyes.

"H-hi?" Izuku said, distinctly reminded of Kacchan for a moment, "Can I he-?" 

His head jerked to the side as the two pointer he had been about to destroy was kicked apart by a tall teen wearing glasses and rolled up pants legs to expose mufflers.

"I've got to go," Izuku said, launching string onto the top of a three story building and pulling himself up. Running to the other side, he watched a purple haired boy stare down a one pointer charging at him. No- "I've got you!" 

A rope of string launched from his sleeve, wrapping around the boy and pulling him to safety at the same time a black haired boy jumped from the alleyway and onto the robot, shattering its head on one strike, "Sorry! Didn't see you up there!"

"It's fine!" Izuku said, smiling, "There's plenty of points to go around. All that matters is that he's safe."

"Right!" The boy said, before running off, "see you around!"

Izuku pushed string to the tips of his fingers, watching a three pointer rush towards an intersection and launching them into a wall as he hopped down. The robot tugged on the string so hard it sent him staggering, but also split the bot in two. Forming a ball of several strings from his right hand, he rushed towards another bot bearing down on a boy with a shark's head and threw it under the robot. 

The string exploded, wrapping around the robot and stopping it dead.

"You take the points," Izuku said to the boy, before rushing off to find more people to help with a smile.

\---X  **Shouta** X---

Aizawa Shouta watched the green haired boy wearing an open gym shirt bind a robot with one arm, the cameras UA employed being strong enough to show the tight strands of string. He gave a quiet huff of laughter. 

This was what he meant, when he said the world wasn't rational or fair. He had spent half a decade inventing Binding Cloth style, and the kid was doing things right at home in it without any training whatsoever.

"What do you think of him?" Ken asked, the Cement Hero looking over.

"He's ok," Shouta said, "Doesn't seem to have anything for directly fighting, yet."

"You mean other than the whole "cutting things to pieces" part?" Nemuri teased, "You can say you like your first impression of someone here, Shouta, we won't tell."

"...Whatever," Shouta said

\--- X  **Tashigi** X---

Tashigi was sure Izuku was doing better than her at the moment. Bakugo too, for that matter. They had Quirks that basically worked ex nihilo, especially Izuku, while she needed some sort of object to use as a weapon, and she hadn't been allowed to bring Shigure with her. So it had taken her a minute to get going as she found a chair in one of the buildings and broke a leg off to use as a makeshift boken until she could get her hands on something metal.

Her Quirk wasn't magic, there was only so much better she could make something with Armament. And while it had been 'cool' to imagine herself as a female Miyamoto Musashi, defeating people with whatever was nearby… it just wasn't practical.

And Izuku and her had tried. At length. Sure, over the years Armament had gotten strong enough that she could reinforce a stick of balsa wood until it could take a hit from Izuku's String Slash… but it didn't survive the second. Meanwhile, while he wasn't using his hardest strings for fairly obvious reasons (her parents were understanding…  _ but _ no amount of understanding would outweigh a shattered, multi-hundred thousand yen katana if their lives weren't on the line. It had probably taken all the understanding to  _ buy _ one in the first place), an Armament enhanced Shigure could and would clash with the same technique over and over again before the layer cracked. 

And speaking of shattered weapons, she should probably replace the wood with something else. Like… there! That stop sign would do the trick!

Ducking under the swinging arm of a two pointer, Tashigi landed feet first on the pole and bent it to a ninety degree angle with an Armament enhanced shoe. Swinging her boken at it, she snapped the sign loose and grabbed it with both hands. Black crawled up the pole and made the writing vanish on the triangular sign before she swung it into the approaching robot. It lodged halfway through and sent the robot collapsing.

"Hey!" Tashigi called to a passing boy made of pure metal as she let go of the pole for a second, Armament fading, "Do you mind breaking this at the sign?"

"Not at all!" He did so, nodding and grinning at her, "Tetsutetsu Tetsutetsu."

"Kurogane Tashigi," she said, hoping that was his name and not some sort of catchphrase of his, "I should probably get going!"

"See you around!" Tetsutetsu said, turning and continuing the way he was heading while Tashigi grabbed her new, metal rod and ran towards the crack of gunfire. She hoped those were baton rounds. Really hoped that.

\--- X  **Katsuki** X---

Katsuki blew another robot to pieces, before launching himself towards with Explosion. This was good, it was a competition to see how strong their Quirks were, and in that there was no way he was gonna lose to Zukai or Specs. Their Quirks weren't as strong as Explosion in a fight!

\---X  **Izuku** X---

Izuku spread the fingers of his right hand, the sharpened end of his strings poking from the tips. After looking to make sure nobody else was trying to take this one, he launched them in a jetfast crack, only the glint of green where the light hit them visible before they punched through the three pointer. 

String Shot retracted just as quickly, sliding back into place. He wondered how Tashigi was doing, he knew she could take care of herself, but they had both been waiting for day for years, and-

" **We've got you now, Hero** !" Izuku watched the pair of three pointers turn the corner together, " **You've been making life difficult for our allies, so we've come to take you down** !"

-and UA apparently made robots smart enough that they could form personalized kill squads, "yeah, that makes sense. can't expect anything less from the school of the greatest heroes. when you're at the top, there's always villains who want to take you-"

Bullets went off with a loud crack, hitting the ground behind Izuku. The green haired boy swung his hand around and spread his index finger and thumb as far apart as physically possible. A string formed along the webbing, snapping forward and tore through the first three pointer's head. Before the second could attack him, a plain, brown haired boy slammed a spinning hand into it from the side, a sheet of metal strapped to it with some tape. Where'd he gotten that from?

"Focus on one of us was a dumb move," he said, stopping the spin, "Thanks for the points."

"Doesn't matter who gets them in the end," Izuku said, "just who gets-"

"I was talking to the robot," he said. Izuku glanced at it, before looking back at the boy.

"I don't think it's gonna answer you," Izuku said, pointing to the hole in the side of the robot's head. The boy sighed.

"I… I can't tell if you're way too nice for your own good or messing with me," he said.

"Could be both," Izuku said, before tilting his head to the side, "Hey."

"What?"

"Thanks for the assist," Izuku said, smiling, "Seriously."

"...I just saw points and took them," the other kid said, "but- cr-"

Izuku turned, watching a one pointer loom from the alley it had rushed through. Jumping back, Izuku swept his right leg down and slashed through the robot with a string axe kick.

"ap, behind you…" The other boy trailed off, mouth hanging, "What's your Quirk? Wind vacuums?"

"String," Izuku said, waving, "We should probably stop standing around."

"Good point," the boy said, "I'm Sen, by the way."

"Izuku," Izuku said, keeping his left hand to its place in his pocket.

\--- X  **Tashigi** X---

Tashigi shattered another robot with a shout of exertion, her shirt hardening as several baton rounds from the second robot, a two pointer, slammed home and sent her flying off it and away from her boken. Armament rapidly fading as she gripped a line of a grappling hook from the broken one.

Good. She might not be as skilled with stuff like this, but her and Izuku had practiced enhancing his strings with Armament for combination Super Moves before. They had yet to find a perfect way to get it going, she couldn't use his strings like he could and she had to be touching either him or the Strings for Armament to take effect… but one of the things they had tried was…

Landing on the wall and kicking off, she winced as she felt her legs skid against the metal as she landed on the second bot knees first. That was gonna be friction burns if she was lucky. Not that she was gonna complain if it was that over scraped knees. She was used to those and worst, honestly.

The "hero training" DVD Izuku had gotten for his birthday from his uncle when they were ten was… well, it was good but it probably should have come with a big warning that your body was gonna hurt a lot for the first few days of following it. Longer if you landed badly.

Snapped the wire of the grappling hook as tight as she could with the slack it still had, Tashigi activated Armament on it, turning it into a makeshift spear and driving it through the robot's head. Once it dropped, she let go with a sigh and jumped off the robot to pick up her boken again. Armament deployed slower this time, not enough that someone who didn't know her would be able to tell, but Tashigi could  _ feel _ it do so. She missed Shigure.

"Wow!" Tashigi whipped around, watching a girl with pink skin and horns slide up to her on a trail of slime… or something, "Where'd you get moves like that?"

"Training," Tashigi said, "a lot of-"

A feeling of impending doom flashed through Tashigi's gut, and she tackled the other girl to the ground as the clawed grappling hook slammed into both of the broken robots. Tashigi turned, grabbing the metal tight as it retracted and slacking her jaw just before she was ripped towards the robot.

Yeah, there was no chance she wasn't ripping up the skin of her dominant hand here. It was just too fast and-

The air was forced from her lungs when she slammed chest first into the robot and rolled across its top until she hit the head. But she hadn't let go of her boken this time, and it wasn't hard to spin in place and slam it into the "skull" of the robot.

Taking the pink girl's hand, she staggered up and drew the boken from the-

What was that buzzer? Was the exam ov-?

Oh, Buddha, that was a big robot…

\--- X  **Izuku** X---

Izuku stared at the robot with a wild grin on his face. So that was the Zero pointer, eh? Looked like a bonus boss in a video game!

Then his grin faded, just a bit, as he realized it was, not remotely slowly but sure as hell "surely", breaking the buildings in its path and sending debris flying. It didn't take a moment for Izuku to consider his options.

His left hand left its place in his pocket as he rushed towards it. A piece of rubble flew through the air and towards a building near Izuku, and in seconds he was swinging a net of ten green strings to meet it. They slid through the rubble like a hot knife through butter, splitting it into fragments and plinking off the building.

They were assessing what they did in a natural disaster, Izuku realized suddenly. Something you couldn't fight, just mitigate the damage of. The robot could have been an earthquake, hurricane or fire just as easily. But why? What was the point if there were no points assigned to it?

Did that matter, really? All that mattered was getting as many people out of there as physically possible.

"Run!" He yelled to a girl with green hair as he slashed another piece of rubble to pieces, "Go!"

"I… God bless you," she bowed, before running off. Izuku turned towards the approaching robot before closing his eyes and planting his hand on the ground. String slithered from his hand like a snake, and he spread his senses along them.

Find them. Someone who needed…

"Help!"

There!

All the strings except for one retracted suddenly and Izuku began to follow it as fast as he could, moving up the wall and across the rooftops as fast as he could. He couldn't afford to let a single second go to waste. Not in this disaster.

\--- X  **Shouta** X---

"He was holding back," Shouta said quietly as Midoriya tore across the rooftops, his legs seeming to bend and distort as he did so. A spike of irritation dug into his gut, before he frowned in confusion. 

Why had the kid been holding back? Arrogance? Had he actually been arrogant enough to think his Quirk was strong enough to get him into UA literally one handed?

But then why was he using it now? Things hadn't really changed for him, beyond the fragments of cement flying through the air. The Zero Point "Executor" robot wasn't programmed to hunt for the leaders or anything of the sort, and they hadn't had anyone beat it in three years. There was no point.

\---X  **Izuku** X---

Faster.

Izuku finished unzipping his sweatshirt as several bullets whizzed passed his head. Pulling his arms through it, he wasted no time slashing another piece of rubble to pieces, the string leading to the girl calling for help clenched between his teeth. It wasn't enough, him and the robot were heading towards the same place now. 

_ Faster _ .

His foot found the sole of his right shoe, and he kicked it off as hard as he could while string pressed against the bottom of his foot. Another two lashed out from his mouth, wrapping around the discarded pieces of clothes.

**String Shave!**

Below him, his sock's bottom was torn to pieces as hundreds of densely packed threads exploded from his foot. The space between him and the girl reduced by meters in a second as he was sent flying in a parabolic arc. Behind him, the strings returned to their place as quickly as possible. 

Slamming into the ground next to the rubble she was trapped under, Izuku panted, "Are you o-? right, stupid question. Of course you aren't. What's you're Quirk?"

"My Quir- Zero Gravity," the girl said, "it lets me reduce the gravity of anything I touch with all five fingers.:

That made things easier, "touch whatever I touch, we'll get you out of here quickly."

Izuku and the girl did exactly that. With him digging sting into each piece of rubble and tossing them up onto the rooftops around them once she had removed the gravity from them. Carefully, Izuku slid her into a piggy back ride as he removed his other shoe.

"Hold on tight," Izuku ordered as he tied his sweatshirt around them both and kicked off his other shoe, aware of the robot bearing down on them.

**String Shave:**

"What are weeeeeaaah-!" She shrieked as they suddenly accelerated, Izuku launching them with both feet.

**Sky's Catapult!**

\---X  **Tashigi** X---

Tashigi walked out of UA with a heavy sigh, her energy sapped a lot from Recovery Girl healing the various bruises she had gotten during the exam. Now it was time to find-

There was (probably) Izuku, perched on the wall around UA like a bird, talking with a brown blur as he cleaned his tinted goggles. Pulling the band over his head, he snapped them tight, green disappearing under… well, green lenses in a move so familiar she'd recognize it even without her glasses. 

Speaking of which, unfortunately. She pulled out the red frames and slid them on her face and blinked a few times as the world came into focus. While she hadn't held much doubt, she confirmed that yes, it was Izuku up there.

"Izuku!" She called, jogging over. He stopped talking, tipped backwards off the wall and hanging upside down with his happy, wild grin on his face.

"Tashigi!" He called back with a laugh, spreading his arm. The hug was awkward, considering he was hanging upside down, but as familiar as always, "Think you passed?"

"Hopefully," Tashigi said, letting go and stepping back, "Do I even need to ask for you?"

"We should never assume something is certain," Izuku said, planting his hands on the ground and letting the string return to its place. For a second he held the handstand, before tipping forwards and onto his feet, "Tashigi, this is Uraraka Ochako. Uraraka, this is Kurogane Tashigi."

"Nice to meet you," Tashigi said, bowing.

"Same," Uraraka said, bowing.

"We should probably get going," Izuku said, cracking his back as he came up from the crouch, "Fullbody is probably waiting for us."

"Yeah," Tashigi said, glancing at the crowd and then towards where her driver had parked the car, "Don't want him to get worried when we're not with the crowd."

"We'll see you around," Izuku said to Uraraka, waving as he walked backwards.

"I thought you said we shouldn't assume nothing is certain?" She said.

"I am!" Izuku said, "We don't know that we won't all get into UA! We don't know we won't see each other again! So let's assume us not seeing you around isn't certain!"

"He's an optimist," Tashigi said, laughing, He's sure we'll get in, he just doesn't want to admit he was trying to sound deep earli-"

"Shhhh!" Izuku put a finger to his lips, even as he huffed out a "Fuffuffuffuffu!"

"We'll see you," Tashigi said, smiling at Uraraka.

\---


End file.
